Re: [RFC PATCH 2/3] cpufreq: Add SW BOOST support for drivers without frequency table

From: Rafael J. Wysocki
Date: Thu May 14 2020 - 10:16:34 EST


On Friday, May 8, 2020 11:11:03 AM CEST Xiongfeng Wang wrote:
> Software-managed BOOST get the boost frequency by check the flag
> CPUFREQ_BOOST_FREQ at driver's frequency table. But some cpufreq driver
> don't have frequency table and use other methods to get the frequency
> range, such CPPC cpufreq driver.
>
> To add SW BOOST support for drivers without frequency table, we add
> members in 'cpufreq_policy.cpufreq_cpuinfo' to record the max frequency
> of boost mode and non-boost mode. The cpufreq driver initialize these two
> members when probing.
>
> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
> ---
> drivers/cpufreq/cpufreq.c | 23 +++++++++++++++--------
> include/linux/cpufreq.h | 2 ++
> 2 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 475fb1b..a299426 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2508,15 +2508,22 @@ static int cpufreq_boost_set_sw(int state)
> int ret = -EINVAL;
>
> for_each_active_policy(policy) {
> - if (!policy->freq_table)
> - continue;
> -
> - ret = cpufreq_frequency_table_cpuinfo(policy,
> + if (policy->freq_table) {
> + ret = cpufreq_frequency_table_cpuinfo(policy,
> policy->freq_table);
> - if (ret) {
> - pr_err("%s: Policy frequency update failed\n",
> - __func__);
> - break;
> + if (ret) {
> + pr_err("%s: Policy frequency update failed\n",
> + __func__);
> + break;
> + }
> + } else if (policy->cpuinfo.boost_max_freq) {
> + if (state)
> + policy->max = policy->cpuinfo.boost_max_freq;
> + else
> + policy->max = policy->cpuinfo.nonboost_max_freq;
> + policy->cpuinfo.max_freq = policy->max;
> + } else {
> + continue;
> }

Why do you need to update this function?

The driver should be able to provide its own ->set_boost callback just fine,
shouldn't it?

>
> ret = freq_qos_update_request(policy->max_freq_req, policy->max);
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 018dce8..c3449e6 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -43,6 +43,8 @@ enum cpufreq_table_sorting {
> struct cpufreq_cpuinfo {
> unsigned int max_freq;
> unsigned int min_freq;
> + unsigned int boost_max_freq;
> + unsigned int nonboost_max_freq;
>
> /* in 10^(-9) s = nanoseconds */
> unsigned int transition_latency;
>